Unlike most Indian teas, Darjeeling tea is normally made from the small-leaved Chinese variety of Camellia sinensis var. sinensis, rather than the large-leaved Assam plant (C. sinensis var. assamica). Traditionally, Darjeeling tea is made as black tea; however, Darjeeling oolong and green teas are becoming more commonly produced and easier to find, and a growing number of estates are also producing white teas. After the enactment of Geographical Indications of Goods (Registration & Protection Act, 1999) in 2003, Darjeeling tea became the first Indian product to receive a GI tag, in 2004-05 through the Indian Patent Office.[2]

Tea planting in the Indian district of Darjeeling began in 1841 by Arthur Campbell,[3] a civil surgeon of the Indian Medical Service. Campbell was transferred to Darjeeling in 1839 from Kathmandu, Nepal. In 1841, he brought seeds of the Chinese tea plant (Camellia sinensis) from Kumaun and began to experiment with tea planting in Darjeeling.[4] The British government also established tea nurseries during that period (1847). Commercial development began during the 1850s.[5] In 1856, the Alubari tea garden was opened by the Kurseong and Darjeeling Tea company,[4] followed by others.[5][6]

Logo of the Darjeeling Tea Association – the central portion is the actual certification mark.

According to the Tea Board of India - "Darjeeling Tea" can only refer to tea that has been cultivated, grown, produced, manufactured and processed in tea gardens (see 'Tea Estates' section below) in the hilly areas of Sadar Subdivision, only hilly areas of Kalimpong Subdivision consisting of Samabeong Tea Estate, Ambiok Tea Estate, Mission Hill Tea Estate and Kumai Tea Estate, and Kurseong Subdivision excluding the areas in jurisdiction list 20, 21, 23, 24, 29, 31 and 33 comprising Siliguri subdivision of New Chumta Tea Estate, Simulbari and Marionbari Tea Estate of Kurseong Police Station in Kurseong Subdivision of the District of Darjeeling in the State of West Bengal, India grown on picturesque steep slopes up to 4000 ft (ca. 1200 m). Tea which has been processed and manufactured in a factory located in the aforesaid area, which, when brewed, has a distinctive, naturally occurring aroma and taste with light tea liquor and the infused leaf of which has a distinctive fragrance.

Adulteration and falsification are serious problems in the global tea trade;[7] as of 2004, the amount of tea sold as Darjeeling worldwide every year exceeds 40,000 tonnes, while the annual tea production of Darjeeling itself is estimated at only 10,000 tonnes, including local consumption. To combat this situation, the Tea Board of India administers the Darjeeling certification mark and logo (see right).[8] Protection of this tea designation is similar in scope to the protected designation of origin used by the EU for many European cheeses. According to the Tea Board, Darjeeling tea cannot be grown or manufactured anywhere else in the world, a labeling restriction similar to the E.U. protections for Champagne and Jamón ibérico.[9]

Traditionally, Darjeeling teas are classified as a type of black tea. However, the modern Darjeeling style employs a hard wither (35-40% remaining leaf weight after withering), which in turn causes an incomplete oxidation for many of the best teas of this designation, which technically makes them a form of oolong. Many Darjeeling teas also appear to be a blend of teas oxidized to levels of green, oolong, and black.

First flush is harvested in mid-March following spring rains, and has a gentle, very light colour, aroma, and mild astringency.

In between is harvested between the two "flush" periods.

Second flush is harvested in June and produces an amber, full bodied, muscatel-flavoured cup.

Monsoon or rains tea is harvested in the monsoon (or rainy season) between second flush and autumnal, is less withered, consequently more oxidized, and usually sold at lower prices. It is rarely exported, and often used in masala chai.

Autumnal flush is harvested in the autumn after the rainy season, and has somewhat less delicate flavour and less spicy tones, but fuller body and darker colour.

Darjeeling white tea brews with a delicate aroma and a pale golden colour.

The white variant of Darjeeling tea has a delicate aroma and brews to a pale golden colour with a mellow taste and a hint of sweetness. Darjeeling white tea leaves are very fluffy and light; therefore, it is recommended to use more (by volume) when preparing it than one normally would for other teas.[10]

The tea is hand-picked and rolled, then withered in the sun, making it a rare tea. It is grown in the rainy and cold climate of Darjeeling at altitudes up to 2000 metres.

The oolong variant of Darjeeling tea has two distinct types: clonal and China. The China type is more similar to Taiwan oolong and the clonal type is totally different from it.[11]

Darjeeling oolong is lighter than usual Darjeeling black tea during first flush, as it is semioxidized. The cup looks light orange and infusion remains green. Darjeeling oolong in second flush is more accepted worldwide. It is more thick in cup and dark orange in liquor with distinct muscatel flavours. The China type oolong has very rare muscatel flavour and sells somewhere around US$40–200 per kg. Clonal oolong has distinct flowery or spicy taste, so is not as well-accepted as Darjeeling oolong worldwide.

Not all Darjeeling gardens are qualified to produce Darjeeling oolong; only those with the following conditions are capable of making it:

Altitudes 3000 ft above sea level are required.

Old China bush (Chesima) concentration should cover at least 40% of total tea-growing area.

Average temperatures should remain between 5 and 20 °C throughout the season.

Lower-elevation gardens can produce teas of similar appearance, but the flavour differs greatly from the main characteristics of oolong tea.

Darjeeling oolong teas are made from finely plucked leaves, usually two leaves and a bud, and are sometimes withered naturally in sun and air. The withered leaves get hand-rolled and pan-fired at certain temperatures. This can also be done in machine: withered in trough, lightly rolled in a rolling machine and fired at 220 °C in a quality dryer with faster run-through, depending on the leaves used.

Darjeeling Tea is also becoming popular because of the Green Tea variant produced by several estates in Darjeeling. Green tea is not fermented at all. It is steamed to stop oxidation before it starts, which preserves most of the polyphenols. It has 60% more polyphenol (antioxidants) content than black tea, and has a less bitter taste.

Polyphenols can help the body protect itself against free radicals; molecules, which occur in the environment and are naturally produced by the body, and can cause damage to cells. Chronic damage by free radicals is one factor thought to contribute to the development of many chronic diseases including heart disease or cancer. Polyphenols scavenge cell-damaging free radicals, which are linked with cancer-causing genes and cause LDL cholesterol to form artery-clogging plaque. The polyphenols in tea possess 25 to 100 times the antioxidant potency of vitamins C and E. Antioxidants impair the ability of free radical cells to harm the molecules that make up our bodies.

Below, Darjeeling tea aficionados will find, a list of tea terms to describe the Darjeeling loose leaf teas in its raw, dry, or infused state.

• Bloom: A term used to refer to the silken sheen, silvery hairy lustre on the tea leaves, resulting from the neat distribution of fine pubescence on the leaf surface.

• Bright: Referring to the infused tea leaves. The hue ranges from lively bright colour, as opposed to dull and varies from a delicate lime green ( with hints of fading coppery ) in the first flush or spring flush tea leaves to a bright copper-purple in second flush tea leaves and to a pale brown in autumn flush tea leaves.

• Colour: It’s a term relating to the hue on dry tea leaves. Each flush has its own particular characteristics . • First Flush Tea Leaves or Spring Tea as it is also commonly called has grayish-greenish. • Second flush tea leaves or the summer tea leaves has a purplish-brown shade. • Autumn Teas, have blackish brown hues.

• Even: A term used for infused leaves for the uniformity of colour and size of the tea leaves.

• Nose/Point: It’s a term referred to the infused leaves for their fragrance which has subtle hints of flowers or fruits or Muscatel character or sometimes showing characteristics of transuding all three combined.

• Stylish: A term used for referring to dry tea leaves which are wiry, neatly twisted and evenly sized.

• Tippy: A term commonly referred to the unopened buds on the tea bush which are transformed into silvery particles called Tips, and which provide an attractive appearance in the ‘finished’ tea.

There are 87 tea estates (also called "tea gardens") in the Darjeeling hills that have been accorded the right to label its produce as "Darjeeling Tea" by the Tea Board of India. These estates cover over 17,500 hectares of land, producing over 9 million kg of tea per year and engaging about 50 percent the people of Darjeeling district. Each estate produces teas with different characteristics of taste and aroma. Most of the tea estates are the members of Indian Tea Association(ITA) and the Darjeeling Tea Association(DTA)

The Touzi Section of the West Bengal government deals with the control and supervision of all tea gardens in the district of Darjeeling as per the provisions of West Bengal Estates Acquisition Act, 1953. All the tea gardens are leased out for a term of 30 years as per Form I, Schedule F of the WBEA Act. The Touzi Section realizes revenues in the form of land rent, penalty, and fines payable by a tea garden to the Collector.[13]

Darjeeling tea has been plagued by management-labour problems for several decades. Frequent lock-outs and low wages have been the chief sources of discontent among the tea garden workers.[14] Tea estate managements have claimed that profits from tea estates have diminished over the years, but have been reluctant to make public their revenue figures, and there has been severe criticism of the tea garden owners and management for the exploitation of the tea garden workers by social workers and political activists.[15]